ASA POWERPLANT ORAL EXAM LATEST EXAM | ALL
QUESTIONS AND CORRECT ANSWERS | ALREADY
GRADED A+ | VERIFIED ANSWERS | STUDY THIS ONE!
What is the main advantage of a horizontally opposed engine over a radial engine
for powering modern aircraft? - (answers)smaller frontal area and easier to
streamline.
How many throws are there in the crankshaft of a six-cylinder horizontally
opposed engine? - (answers)six
What kind of connecting rod arrangement is used in a radial engine? - (answers)a
master rod connects the single throw of the crankshaft with a piston. all other
pistons are connected to the master rod with link rods
Of what material are most piston rings made? - (answers)grey cast iron
What is the reason for using hydraulic valve lifters in an aircraft engine? -
(answers)keep all of the clearance out of the valve operating mechanism,
decreases wear of valve train components
At what speed does the camshaft turn, relative to the crankshaft speed in a
horizontally opposed engine? - (answers)camshaft is one half the speed of
crankshaft
What kind of main bearings are used in a horizontally opposed engine? -
(answers)steel backed lead alloy bearings
,On what stroke is the piston of a reciprocating engine when the intake valve
begins to open? - (answers)exhaust
On what stroke is the piston of a reciprocating engine when the exhaust valve
begins to open? - (answers)power
Why are both the hot and cold valve clearances given for most radial engines? -
(answers)hot clearance is for valve timing. timing adjusted with valves in cylinder
1 set with hot clearance then adjusted to cold clearance
What is meant by a cam-ground piston - (answers)A piston that is not perfectly
round. . When the piston reaches operating temperature, the metal expands
enough that the piston becomes perfectly round.
Where is the piston in a reciprocating engine when the ignition spark occurs? -
(answers)before top dead center on the compression stroke
What is meant by a full-floating wrist pin? - (answers)pin not clamped in either
piston or connecting rod
Why do most aircraft reciprocating engines use more than one spring on each
valve? - (answers)for different frequencies/rpms
,Would excessive valve clearance cause the valves to open early or late? -
(answers)open late close early
What is the purpose of valve overlap in a reciprocating engine? - (answers)Valve
overlap allows the inertia of the exhaust gases leaving the cylinder to help the
fresh induction charge start flowing into the cylinder.
What type of piston rings are installed on the pistons of an aircraft reciprocating
engine? - (answers)compression, oil control, oil wiper
Why are some exhaust valves partially filled with metallic sodium? - (answers)The
metallic sodium melts at engine operating temperature It picks up heat from the
valve head and transfers it into the valve stem, so it can be transferred to the
cylinder head through the valve guide
What causes detonation in an aircraft engine? - (answers)Excessive heat and
pressure in the engine cylinder , the mixture explodes rather than burns.
Why is a compression check important for determining the condition of an
aircraft reciprocating engine? - (answers)to check condition of seals between
piston ring and cylinder wall and valves and thier seats
What is meant by the compression ratio of a reciprocating engine? -
(answers)ratio of volume of cylinder with piston at bottom vs piston at top
, What are the two basic sections of a turbine engine? - (answers)hot and cold
What are the two basic types of compressors that are used in aircraft turbine
engines? - (answers)axial flow and centrifugal
What is the purpose of the stators in an axial-flow compressor? -
(answers)convert velocity energy to pressure energy and change direction of air
What are three types of combustors used on aircraft turbine engines? -
(answers)can, annular, can-annular
How many igniters are there normally in an aircraft turbine engine? -
(answers)two
What is the main purpose of the turbine nozzle in an aircraft turbine engine? -
(answers)direct gasses as they leave combustors so they will turn turbine wheel
with maximum efficiency
What is meant by a free-turbine turboshaft engine - (answers)A turboshaft engine
that has a turbine wheel, that is not used to drive the compressor of the gas
generator section of the engine. This free turbine drives the propeller in a
turboprop engine or the transmission and rotor of a helicopter.
Why do some axial-flow turbine engines have more than one set of turbines and
compressors - (answers)A two-spool turbine engine has a low-pressure and a
QUESTIONS AND CORRECT ANSWERS | ALREADY
GRADED A+ | VERIFIED ANSWERS | STUDY THIS ONE!
What is the main advantage of a horizontally opposed engine over a radial engine
for powering modern aircraft? - (answers)smaller frontal area and easier to
streamline.
How many throws are there in the crankshaft of a six-cylinder horizontally
opposed engine? - (answers)six
What kind of connecting rod arrangement is used in a radial engine? - (answers)a
master rod connects the single throw of the crankshaft with a piston. all other
pistons are connected to the master rod with link rods
Of what material are most piston rings made? - (answers)grey cast iron
What is the reason for using hydraulic valve lifters in an aircraft engine? -
(answers)keep all of the clearance out of the valve operating mechanism,
decreases wear of valve train components
At what speed does the camshaft turn, relative to the crankshaft speed in a
horizontally opposed engine? - (answers)camshaft is one half the speed of
crankshaft
What kind of main bearings are used in a horizontally opposed engine? -
(answers)steel backed lead alloy bearings
,On what stroke is the piston of a reciprocating engine when the intake valve
begins to open? - (answers)exhaust
On what stroke is the piston of a reciprocating engine when the exhaust valve
begins to open? - (answers)power
Why are both the hot and cold valve clearances given for most radial engines? -
(answers)hot clearance is for valve timing. timing adjusted with valves in cylinder
1 set with hot clearance then adjusted to cold clearance
What is meant by a cam-ground piston - (answers)A piston that is not perfectly
round. . When the piston reaches operating temperature, the metal expands
enough that the piston becomes perfectly round.
Where is the piston in a reciprocating engine when the ignition spark occurs? -
(answers)before top dead center on the compression stroke
What is meant by a full-floating wrist pin? - (answers)pin not clamped in either
piston or connecting rod
Why do most aircraft reciprocating engines use more than one spring on each
valve? - (answers)for different frequencies/rpms
,Would excessive valve clearance cause the valves to open early or late? -
(answers)open late close early
What is the purpose of valve overlap in a reciprocating engine? - (answers)Valve
overlap allows the inertia of the exhaust gases leaving the cylinder to help the
fresh induction charge start flowing into the cylinder.
What type of piston rings are installed on the pistons of an aircraft reciprocating
engine? - (answers)compression, oil control, oil wiper
Why are some exhaust valves partially filled with metallic sodium? - (answers)The
metallic sodium melts at engine operating temperature It picks up heat from the
valve head and transfers it into the valve stem, so it can be transferred to the
cylinder head through the valve guide
What causes detonation in an aircraft engine? - (answers)Excessive heat and
pressure in the engine cylinder , the mixture explodes rather than burns.
Why is a compression check important for determining the condition of an
aircraft reciprocating engine? - (answers)to check condition of seals between
piston ring and cylinder wall and valves and thier seats
What is meant by the compression ratio of a reciprocating engine? -
(answers)ratio of volume of cylinder with piston at bottom vs piston at top
, What are the two basic sections of a turbine engine? - (answers)hot and cold
What are the two basic types of compressors that are used in aircraft turbine
engines? - (answers)axial flow and centrifugal
What is the purpose of the stators in an axial-flow compressor? -
(answers)convert velocity energy to pressure energy and change direction of air
What are three types of combustors used on aircraft turbine engines? -
(answers)can, annular, can-annular
How many igniters are there normally in an aircraft turbine engine? -
(answers)two
What is the main purpose of the turbine nozzle in an aircraft turbine engine? -
(answers)direct gasses as they leave combustors so they will turn turbine wheel
with maximum efficiency
What is meant by a free-turbine turboshaft engine - (answers)A turboshaft engine
that has a turbine wheel, that is not used to drive the compressor of the gas
generator section of the engine. This free turbine drives the propeller in a
turboprop engine or the transmission and rotor of a helicopter.
Why do some axial-flow turbine engines have more than one set of turbines and
compressors - (answers)A two-spool turbine engine has a low-pressure and a
